Cruise lines and airlines say they’re taking extra precautions to protect passengers and crew members against the threat of the H1N1 flu and seasonal flu.

Since last spring, 50 million Americans have been sickened with H1N1, also known as swine flu, and nearly 10,000 have died, according to U.S. Centers for Disease Control and Prevention figures. Reports of new H1N1 cases have leveled off in recent weeks, the agency says, but the threat remains and is expected to continue well into spring.

As a result, health authorities are urging people to avoid crowded areas.

Asked what new or unusual safeguards, if any, are in place and whether crew members are being given the H1N1 vaccine, Julie Benson, Princess Cruises public relations director, said, “We treat all flulike illness.”

She said the cruise line screens passengers and crew for symptoms, isolates and medicates anyone with flu, and “rigorously” sanitizes ships with a disinfectant “proven to be highly effective against the flu.” Further, crew members receive seasonal flu shots and will receive the H1N1 vaccine as it’s available.

Lufthansa Airlines spokeswoman Jennifer Urbaniak said regular flu vaccines have been given to employees, and staffers who deal with the public are being urged to get the swine flu vaccination.

“As the largest European airline in Asia, we’ve already gone through this with SARS, and not a single case of transmission on board was found then,” she said. “The risk of contraction on board is quite low due to the high-quality filters, which are as effective as those found in a hospital operating room.”

Bryan Baldwin, JetBlue Airways corporate communications manager, said all flights have kits containing alcohol wipes, extra gloves and five masks available for ill passengers. “In addition,” he added, “we use the latest high-efficiency particulate arresters, and the total cabin air content on each of our aircraft is replaced more than 30 times an hour, far exceeding the exchange rate in an office building.”

Vance Gulliksen, Carnival Cruise Line spokesman, said the line uses “every stringent recommended sanitation protocol” and that crew members are receiving H1N1 shots. Further, passengers are screened for symptoms before boarding.

“Anyone who has an illness of international public concern isn’t permitted to sail,” he said.

Seabourn Cruise Line also screens passengers and doesn’t allow the ill to board, said public relations director Bruce Good. Further, “We carry supplies of Tamiflu medication, which has proven to be effective in cases of H1N1.”

Michael Crye, a vice president of the trade group Cruise Line International Association, said his organization works with major health organizations worldwide, supplying members with information and facilitating meetings. However, it doesn’t tell cruise lines what to do.

“Each cruise line has its own medical doctors, and they’re quite capable of making their own decisions,” he said.

With the usual bon voyage signs, cruisers are finding these CDC recommendations in their staterooms:

• Wash your hands often with soap and water, especially after you cough or sneeze. Alcohol-based hand cleaners also can be effective.

• Cover your nose with a tissue or your arm when you cough or sneeze.

• Avoid touching your eyes, nose or mouth. Germs spread that way.

Si Liberman is a freelance writer in Florida.